This invention relates generally to turbine engines, more particularly to methods and apparatus to facilitate generating power from a turbine engine.
A conventional gas turbine engine generally includes a compressor and turbine arranged on a rotating shaft(s), and a combustion section between the compressor and turbine. The combustion section burns a mixture of compressed air and liquid and/or gaseous fuel to generate a high-energy combustion gas stream that drives the rotating turbine. The turbine rotationally drives the compressor and provides output power. Industrial gas turbines are often used to provide output power to drive an electrical generator or motor. Other types of gas turbines may be used as aircraft engines, on-site and supplemental power generators, and for other applications.
In an effort to improve the efficiency of gas turbine engines, pulse detonation engines (PDE) have been purposed. In a generalized PDE, fuel and oxidizer (e.g., oxygen-containing gas such as air) are admitted to an elongated combustion chamber at an upstream inlet end. An igniter is utilized to detonate this charge (either directly or through a deflagration-to-detonation transition (DDT)). A detonation wave propagates toward the outlet at supersonic speed causing substantial combustion of the fuel/air mixture before the mixture can be substantially driven from the outlet. The result of the combustion is to rapidly elevate pressure within the chamber before substantial gas can escape inertially through the outlet. The effect of this inertial confinement is to produce near constant volume combustion.
The PDE can be positioned as an augmentor or as the main combustor or both. Only recently has pulse detonation been purposed for use in the main combustor. One main challenge in developing pulse detonation engines having a pulse detonation combustor (PDC) is understanding and overcoming the effects of high-pressure pulses (decaying blast waves) on turbine performance and life of the engine. Furthermore, such pulse detonation engines generally do not have turbine designs that are optimized to produce steady and spatially uniform flow fields.
Typically, a PDC cycles through a variety of processes such as, for example, a fill process, a high pressure detonation wave, a supersonic blowdown, a subsonic blowdown, and a purge process. At least one challenge in optimizing pulse detonation engines is to design the geometry of the turbine blades to facilitate extracting the maximum amount of power from each PDC cycle. Consequently, coupling the operation of each turbine blade to a respective PDC process may be critical to reducing flow losses, increasing engine efficiency, and to increasing power.